I would have tried to do it with an ATtiny85 and a Neopixel. $1.25 for an Arduino compatible chip. The neopixel is a single pin 3 color led using a special library. http://highlowtech.org/?p=1695https://www.sparkfun.com/products/11801I use ATtiny85s for all of my projects. My philosophy is why pay for a full Arduino board when all you need is a couple IO pins.